It is known from DE 27 51 761, EP 0 198 519 and EP 0 192 304 to use specific urea compounds as sag control agents in liquid coating compositions. In certain liquid coating compositions, these urea compounds may give rise to unwanted haze phenomena in the coating layers applied and cured therefrom. It is known from U.S. Pat. No. 6,355,307 to overcome this haze problem in clear coats applied and cured from liquid clear coating compositions which do not cure by means of amino resin cross-linkers by simultaneously using small quantities of formaldehyde donors in the liquid clear coating compositions in addition to the urea compounds used as sag control agents.
It has now been found that specific polyurethane resins may successfully be used as sag control agents in liquid coating compositions based on hydroxyl-functional binders. Such liquid coating compositions require no addition of formaldehyde donors, even if they contain no amino resin.